I personally love this time of the year on the island because there are fewer people in Acadia meaning you get a much less crowded experience! In addition to Acadia National Park, the island is also home to many coastal towns; the park winds in and out of these towns meaning that it is never far away and is always accessible. Looking ahead at the weather, it looks like it will be windy but not too cold during your stay- just pack lots of layers to make sure you can enjoy your time! Below are some recommendations- I've broken them up into clusters of what I think would fit well together based on the locations but all could be done individually! Most are outdoor activities but we do have a fireplace and lots of hot beverages and wine to warm you up at the end of the day here at the Inn :)
I hope this helps! I love to explore this island and am so happy to show you on a map where each of these places are as well as show you pictures! Safe travels!